When low-cost consumer type VCR systems, such as the current popular VHS system, were invented, the major objective was to provide recording capability for the purpose of time-shifting television programming. Unfortunately, the performance of the now popular VCR formats was compromised in order to counteract the introduction of Video Disc systems which had the potential during VCR infancy to decrease the market share for VCR's. As a result, video recorders suffered from low picture quality (e.g., only 2.5 MHz bandwidth was provided for the luminance component as compared with the NTSC (National Television Systems Committee) bandwidth of 4.2 MHz. But VCR's won in popularity over the Video Disk. Furthermore, because no careful evaluation took place, these early recording formats were not designed with the vision in mind to later develop compatible upgrades to the full NTSC signal spectrum.
Later development efforts resulted in several improved recording formats, such as the Super VHS (S-VHS) system which addressed this lack of quality, but the new formats with better performance were incompatible with the existing, standard, equipment (e.g., home VCR's as well as tape duplication machines for the rental market). This lack of compatibility has prevented these systems from gaining widespread acceptance, particularly due to the large number of existing VCR machines in the marketplace, as well as the great quantity of existing pre-recorded tapes in the old formats (both rental and privately owned). For example, the S- VHS system achieved an upward scaling of performance by use of improved bandwidth handling capabilities of the tape and the recording/playback heads. This, together with a shift to higher recording frequencies, allowed S-VHS quality to exceed the standard NTSC performance but rendered the format unsuitable for playback by standard VHS players, thus preventing the S-VHS system from gaining widespread acceptance and use.
It is an object of the present invention to provide a recording format which provides full compatibility with the existing formats and which yields picture performance equivalent to that of full NTSC by augmenting the standard recording formats.
It is a further object of the invention that video tapes recorded by this new augmented format can be played by (i.e., are backward compatible with) the standard VCR's and that tapes recorded in the standard formats can be played back in a VCR designed in accordance with this new tape recording format.